Hi All I'm looking for a keypad program in c that uses the 74c922 encoder chip. A 3x4 keypad is used. I'm really struggling with this. Can anyone help me? How do you wright the program so that the eprom can tell what keypad has been pressed according the encoder chip? Any help would be greatly appreceated! Regards
Yes, But how do impliment the code to tell it to look for the data there? And do you need a ASCII table as well?
"But how do impliment the code to tell it to look for the data there?" You don't need to implement any code yourself. Just crosspost your question to as many newsgroups as possible until someone does it for you. What could be simpler than that?
"But how do impliment the code to tell it to look for the data there?" You simply examine the state of the DATA AVAILABLE output pin - its sole purpose in life is to tell you when there's data available. "And do you need a ASCII table as well?" As I pointed out to you before, the Truth Table on p2 of the data sheet tells you what codes the chip will output for each key in your keypad. If you want a different encoding you will, of course, have to do that yourself - or find a different chip that provides the encoding you require!